includes/Revision.php

   1 <?php
   2 /**
   3  * @todo document
   4  */
   5
   6 /**
   7  * @todo document
   8  */
   9 class Revision {
  10         const DELETED_TEXT = 1;
  11         const DELETED_COMMENT = 2;
  12         const DELETED_USER = 4;
  13         const DELETED_RESTRICTED = 8;
  14
  15         /**
  16          * Load a page revision from a given revision ID number.
  17          * Returns null if no such revision can be found.
  18          *
  19          * @param int $id
  20          * @access public
  21          * @static
  22          */
  23         public static function newFromId( $id ) {
  24                 return Revision::newFromConds(
  25                         array( 'page_id=rev_page',
  26                                'rev_id' => intval( $id ) ) );
  27         }
  28
  29         /**
  30          * Load either the current, or a specified, revision
  31          * that's attached to a given title. If not attached
  32          * to that title, will return null.
  33          *
  34          * @param Title $title
  35          * @param int $id
  36          * @return Revision
  37          * @access public
  38          * @static
  39          */
  40         public static function newFromTitle( &$title, $id = 0 ) {
  41                 if( $id ) {
  42                         $matchId = intval( $id );
  43                 } else {
  44                         $matchId = 'page_latest';
  45                 }
  46                 return Revision::newFromConds(
  47                         array( "rev_id=$matchId",
  48                                'page_id=rev_page',
  49                                'page_namespace' => $title->getNamespace(),
  50                                'page_title'     => $title->getDbkey() ) );
  51         }
  52
  53         /**
  54          * Load a page revision from a given revision ID number.
  55          * Returns null if no such revision can be found.
  56          *
  57          * @param Database $db
  58          * @param int $id
  59          * @access public
  60          * @static
  61          */
  62         public static function loadFromId( &$db, $id ) {
  63                 return Revision::loadFromConds( $db,
  64                         array( 'page_id=rev_page',
  65                                'rev_id' => intval( $id ) ) );
  66         }
  67
  68         /**
  69          * Load either the current, or a specified, revision
  70          * that's attached to a given page. If not attached
  71          * to that page, will return null.
  72          *
  73          * @param Database $db
  74          * @param int $pageid
  75          * @param int $id
  76          * @return Revision
  77          * @access public
  78          * @static
  79          */
  80         public static function loadFromPageId( $db, $pageid, $id = 0 ) {
  81                 $conds=array('page_id=rev_page','rev_page'=>intval( $pageid ), 'page_id'=>intval( $pageid ));
  82                 if( $id ) {
  83                         $conds['rev_id']=intval($id);
  84                 } else {
  85                         $conds[]='rev_id=page_latest';
  86                 }
  87                 return Revision::loadFromConds( $db, $conds );
  88         }
  89
  90         /**
  91          * Load either the current, or a specified, revision
  92          * that's attached to a given page. If not attached
  93          * to that page, will return null.
  94          *
  95          * @param Database $db
  96          * @param Title $title
  97          * @param int $id
  98          * @return Revision
  99          * @access public
 100          * @static
 101          */
 102         public static function loadFromTitle( &$db, $title, $id = 0 ) {
 103                 if( $id ) {
 104                         $matchId = intval( $id );
 105                 } else {
 106                         $matchId = 'page_latest';
 107                 }
 108                 return Revision::loadFromConds(
 109                         $db,
 110                         array( "rev_id=$matchId",
 111                                'page_id=rev_page',
 112                                'page_namespace' => $title->getNamespace(),
 113                                'page_title'     => $title->getDbkey() ) );
 114         }
 115
 116         /**
 117          * Load the revision for the given title with the given timestamp.
 118          * WARNING: Timestamps may in some circumstances not be unique,
 119          * so this isn't the best key to use.
 120          *
 121          * @param Database $db
 122          * @param Title $title
 123          * @param string $timestamp
 124          * @return Revision
 125          * @access public
 126          * @static
 127          */
 128         public static function loadFromTimestamp( &$db, &$title, $timestamp ) {
 129                 return Revision::loadFromConds(
 130                         $db,
 131                         array( 'rev_timestamp'  => $db->timestamp( $timestamp ),
 132                                'page_id=rev_page',
 133                                'page_namespace' => $title->getNamespace(),
 134                                'page_title'     => $title->getDbkey() ) );
 135         }
 136
 137         /**
 138          * Given a set of conditions, fetch a revision.
 139          *
 140          * @param array $conditions
 141          * @return Revision
 142          * @access private
 143          * @static
 144          */
 145         private static function newFromConds( $conditions ) {
 146                 $db = wfGetDB( DB_SLAVE );
 147                 $row = Revision::loadFromConds( $db, $conditions );
 148                 if( is_null( $row ) ) {
 149                         $dbw = wfGetDB( DB_MASTER );
 150                         $row = Revision::loadFromConds( $dbw, $conditions );
 151                 }
 152                 return $row;
 153         }
 154
 155         /**
 156          * Given a set of conditions, fetch a revision from
 157          * the given database connection.
 158          *
 159          * @param Database $db
 160          * @param array $conditions
 161          * @return Revision
 162          * @access private
 163          * @static
 164          */
 165         private static function loadFromConds( $db, $conditions ) {
 166                 $res = Revision::fetchFromConds( $db, $conditions );
 167                 if( $res ) {
 168                         $row = $res->fetchObject();
 169                         $res->free();
 170                         if( $row ) {
 171                                 $ret = new Revision( $row );
 172                                 return $ret;
 173                         }
 174                 }
 175                 $ret = null;
 176                 return $ret;
 177         }
 178
 179         /**
 180          * Return a wrapper for a series of database rows to
 181          * fetch all of a given page's revisions in turn.
 182          * Each row can be fed to the constructor to get objects.
 183          *
 184          * @param Title $title
 185          * @return ResultWrapper
 186          * @access public
 187          * @static
 188          */
 189         public static function fetchAllRevisions( &$title ) {
 190                 return Revision::fetchFromConds(
 191                         wfGetDB( DB_SLAVE ),
 192                         array( 'page_namespace' => $title->getNamespace(),
 193                                'page_title'     => $title->getDbkey(),
 194                                'page_id=rev_page' ) );
 195         }
 196
 197         /**
 198          * Return a wrapper for a series of database rows to
 199          * fetch all of a given page's revisions in turn.
 200          * Each row can be fed to the constructor to get objects.
 201          *
 202          * @param Title $title
 203          * @return ResultWrapper
 204          * @access public
 205          * @static
 206          */
 207         public static function fetchRevision( &$title ) {
 208                 return Revision::fetchFromConds(
 209                         wfGetDB( DB_SLAVE ),
 210                         array( 'rev_id=page_latest',
 211                                'page_namespace' => $title->getNamespace(),
 212                                'page_title'     => $title->getDbkey(),
 213                                'page_id=rev_page' ) );
 214         }
 215
 216         /**
 217          * Given a set of conditions, return a ResultWrapper
 218          * which will return matching database rows with the
 219          * fields necessary to build Revision objects.
 220          *
 221          * @param Database $db
 222          * @param array $conditions
 223          * @return ResultWrapper
 224          * @access private
 225          * @static
 226          */
 227         private static function fetchFromConds( $db, $conditions ) {
 228                 $res = $db->select(
 229                         array( 'page', 'revision' ),
 230                         array( 'page_namespace',
 231                                'page_title',
 232                                'page_latest',
 233                                'rev_id',
 234                                'rev_page',
 235                                'rev_text_id',
 236                                'rev_comment',
 237                                'rev_user_text',
 238                                'rev_user',
 239                                'rev_minor_edit',
 240                                'rev_timestamp',
 241                                'rev_deleted',
 242                                'rev_len' ),
 243                         $conditions,
 244                         'Revision::fetchRow',
 245                         array( 'LIMIT' => 1 ) );
 246                 $ret = $db->resultObject( $res );
 247                 return $ret;
 248         }
 249
 250         /**
 251          * Return the list of revision fields that should be selected to create
 252          * a new revision.
 253          */
 254         static function selectFields() {
 255                 return array(
 256                         'rev_id',
 257                         'rev_page',
 258                         'rev_text_id',
 259                         'rev_timestamp',
 260                         'rev_comment',
 261                         'rev_minor_edit',
 262                         'rev_user',
 263                         'rev_user_text,'.
 264                         'rev_deleted',
 265                         'rev_len'
 266                 );
 267         }
 268
 269         /**
 270          * @param object $row
 271          * @access private
 272          */
 273         function Revision( $row ) {
 274                 if( is_object( $row ) ) {
 275                         $this->mId        = intval( $row->rev_id );
 276                         $this->mPage      = intval( $row->rev_page );
 277                         $this->mTextId    = intval( $row->rev_text_id );
 278                         $this->mComment   =         $row->rev_comment;
 279                         $this->mUserText  =         $row->rev_user_text;
 280                         $this->mUser      = intval( $row->rev_user );
 281                         $this->mMinorEdit = intval( $row->rev_minor_edit );
 282                         $this->mTimestamp =         $row->rev_timestamp;
 283                         $this->mDeleted   = intval( $row->rev_deleted );
 284
 285                         if( !isset( $row->rev_len ) || is_null( $row->rev_len ) )
 286                                 $this->mSize = null;
 287                         else
 288                                 $this->mSize = intval( $row->rev_len );
 289
 290                         if( isset( $row->page_latest ) ) {
 291                                 $this->mCurrent   = ( $row->rev_id == $row->page_latest );
 292                                 $this->mTitle     = Title::makeTitle( $row->page_namespace,
 293                                                                       $row->page_title );
 294                         } else {
 295                                 $this->mCurrent = false;
 296                                 $this->mTitle = null;
 297                         }
 298
 299                         // Lazy extraction...
 300                         $this->mText      = null;
 301                         if( isset( $row->old_text ) ) {
 302                                 $this->mTextRow = $row;
 303                         } else {
 304                                 // 'text' table row entry will be lazy-loaded
 305                                 $this->mTextRow = null;
 306                         }
 307                 } elseif( is_array( $row ) ) {
 308                         // Build a new revision to be saved...
 309                         global $wgUser;
 310
 311                         $this->mId        = isset( $row['id']         ) ? intval( $row['id']         ) : null;
 312                         $this->mPage      = isset( $row['page']       ) ? intval( $row['page']       ) : null;
 313                         $this->mTextId    = isset( $row['text_id']    ) ? intval( $row['text_id']    ) : null;
 314                         $this->mUserText  = isset( $row['user_text']  ) ? strval( $row['user_text']  ) : $wgUser->getName();
 315                         $this->mUser      = isset( $row['user']       ) ? intval( $row['user']       ) : $wgUser->getId();
 316                         $this->mMinorEdit = isset( $row['minor_edit'] ) ? intval( $row['minor_edit'] ) : 0;
 317                         $this->mTimestamp = isset( $row['timestamp']  ) ? strval( $row['timestamp']  ) : wfTimestamp( TS_MW );
 318                         $this->mDeleted   = isset( $row['deleted']    ) ? intval( $row['deleted']    ) : 0;
 319                         $this->mSize      = isset( $row['len']        ) ? intval( $row['len']        ) : null;
 320
 321                         // Enforce spacing trimming on supplied text
 322                         $this->mComment   = isset( $row['comment']    ) ?  trim( strval( $row['comment'] ) ) : null;
 323                         $this->mText      = isset( $row['text']       ) ? rtrim( strval( $row['text']    ) ) : null;
 324                         $this->mTextRow   = null;
 325
 326                         $this->mTitle     = null; # Load on demand if needed
 327                         $this->mCurrent   = false;
 328                         # If we still have no len_size, see it we have the text to figure it out
 329                         if ( !$this->mSize )
 330                                 $this->mSize      = is_null($this->mText) ? null : strlen($this->mText);
 331                 } else {
 332                         throw new MWException( 'Revision constructor passed invalid row format.' );
 333                 }
 334         }
 335
 336         /**#@+
 337          * @access public
 338          */
 339
 340         /**
 341          * @return int
 342          */
 343         function getId() {
 344                 return $this->mId;
 345         }
 346
 347         /**
 348          * @return int
 349          */
 350         function getTextId() {
 351                 return $this->mTextId;
 352         }
 353
 354         /**
 355          * Returns the length of the text in this revision, or null if unknown.
 356          */
 357         function getSize() {
 358                 return $this->mSize;
 359         }
 360
 361         /**
 362          * Returns the title of the page associated with this entry.
 363          * @return Title
 364          */
 365         function getTitle() {
 366                 if( isset( $this->mTitle ) ) {
 367                         return $this->mTitle;
 368                 }
 369                 $dbr = wfGetDB( DB_SLAVE );
 370                 $row = $dbr->selectRow(
 371                         array( 'page', 'revision' ),
 372                         array( 'page_namespace', 'page_title' ),
 373                         array( 'page_id=rev_page',
 374                                'rev_id' => $this->mId ),
 375                         'Revision::getTitle' );
 376                 if( $row ) {
 377                         $this->mTitle = Title::makeTitle( $row->page_namespace,
 378                                                            $row->page_title );
 379                 }
 380                 return $this->mTitle;
 381         }
 382
 383         /**
 384          * Set the title of the revision
 385          * @param Title $title
 386          */
 387         function setTitle( $title ) {
 388                 $this->mTitle = $title;
 389         }
 390
 391         /**
 392          * @return int
 393          */
 394         function getPage() {
 395                 return $this->mPage;
 396         }
 397
 398         /**
 399          * Fetch revision's user id if it's available to all users
 400          * @return int
 401          */
 402         function getUser() {
 403                 if( $this->isDeleted( self::DELETED_USER ) ) {
 404                         return 0;
 405                 } else {
 406                         return $this->mUser;
 407                 }
 408         }
 409
 410         /**
 411          * Fetch revision's user id without regard for the current user's permissions
 412          * @return string
 413          */
 414         function getRawUser() {
 415                 return $this->mUser;
 416         }
 417
 418         /**
 419          * Fetch revision's username if it's available to all users
 420          * @return string
 421          */
 422         function getUserText() {
 423                 if( $this->isDeleted( self::DELETED_USER ) ) {
 424                         return "";
 425                 } else {
 426                         return $this->mUserText;
 427                 }
 428         }
 429
 430         /**
 431          * Fetch revision's username without regard for view restrictions
 432          * @return string
 433          */
 434         function getRawUserText() {
 435                 return $this->mUserText;
 436         }
 437
 438         /**
 439          * Fetch revision comment if it's available to all users
 440          * @return string
 441          */
 442         function getComment() {
 443                 if( $this->isDeleted( self::DELETED_COMMENT ) ) {
 444                         return "";
 445                 } else {
 446                         return $this->mComment;
 447                 }
 448         }
 449
 450         /**
 451          * Fetch revision comment without regard for the current user's permissions
 452          * @return string
 453          */
 454         function getRawComment() {
 455                 return $this->mComment;
 456         }
 457
 458         /**
 459          * @return bool
 460          */
 461         function isMinor() {
 462                 return (bool)$this->mMinorEdit;
 463         }
 464
 465         /**
 466          * int $field one of DELETED_* bitfield constants
 467          * @return bool
 468          */
 469         function isDeleted( $field ) {
 470                 return ($this->mDeleted & $field) == $field;
 471         }
 472
 473         /**
 474          * Fetch revision text if it's available to all users
 475          * @return string
 476          */
 477         function getText() {
 478                 if( $this->isDeleted( self::DELETED_TEXT ) ) {
 479                         return "";
 480                 } else {
 481                         return $this->getRawText();
 482                 }
 483         }
 484
 485         /**
 486          * Fetch revision text without regard for view restrictions
 487          * @return string
 488          */
 489         function getRawText() {
 490                 if( is_null( $this->mText ) ) {
 491                         // Revision text is immutable. Load on demand:
 492                         $this->mText = $this->loadText();
 493                 }
 494                 return $this->mText;
 495         }
 496
 497         /**
 498          * Fetch revision text if it's available to THIS user
 499          * @return string
 500          */
 501         function revText() {
 502                 if( !$this->userCan( self::DELETED_TEXT ) ) {
 503                         return "";
 504                 } else {
 505                         return $this->getRawText();
 506                 }
 507         }
 508
 509         /**
 510          * @return string
 511          */
 512         function getTimestamp() {
 513                 return wfTimestamp(TS_MW, $this->mTimestamp);
 514         }
 515
 516         /**
 517          * @return bool
 518          */
 519         function isCurrent() {
 520                 return $this->mCurrent;
 521         }
 522
 523         /**
 524          * @return Revision
 525          */
 526         function getPrevious() {
 527                 $prev = $this->mTitle->getPreviousRevisionID( $this->mId );
 528                 if ( $prev ) {
 529                         return Revision::newFromTitle( $this->mTitle, $prev );
 530                 } else {
 531                         return null;
 532                 }
 533         }
 534
 535         /**
 536          * @return Revision
 537          */
 538         function getNext() {
 539                 $next = $this->mTitle->getNextRevisionID( $this->mId );
 540                 if ( $next ) {
 541                         return Revision::newFromTitle( $this->mTitle, $next );
 542                 } else {
 543                         return null;
 544                 }
 545         }
 546         /**#@-*/
 547
 548         /**
 549           * Get revision text associated with an old or archive row
 550           * $row is usually an object from wfFetchRow(), both the flags and the text
 551           * field must be included
 552           * @static
 553           * @param integer $row Id of a row
 554           * @param string $prefix table prefix (default 'old_')
 555           * @return string $text|false the text requested
 556           */
 557         public static function getRevisionText( $row, $prefix = 'old_' ) {
 558                 $fname = 'Revision::getRevisionText';
 559                 wfProfileIn( $fname );
 560
 561                 # Get data
 562                 $textField = $prefix . 'text';
 563                 $flagsField = $prefix . 'flags';
 564
 565                 if( isset( $row->$flagsField ) ) {
 566                         $flags = explode( ',', $row->$flagsField );
 567                 } else {
 568                         $flags = array();
 569                 }
 570
 571                 if( isset( $row->$textField ) ) {
 572                         $text = $row->$textField;
 573                 } else {
 574                         wfProfileOut( $fname );
 575                         return false;
 576                 }
 577
 578                 # Use external methods for external objects, text in table is URL-only then
 579                 if ( in_array( 'external', $flags ) ) {
 580                         $url=$text;
 581                         @list(/* $proto */,$path)=explode('://',$url,2);
 582                         if ($path=="") {
 583                                 wfProfileOut( $fname );
 584                                 return false;
 585                         }
 586                         $text=ExternalStore::fetchFromURL($url);
 587                 }
 588
 589                 // If the text was fetched without an error, convert it
 590                 if ( $text !== false ) {
 591                         if( in_array( 'gzip', $flags ) ) {
 592                                 # Deal with optional compression of archived pages.
 593                                 # This can be done periodically via maintenance/compressOld.php, and
 594                                 # as pages are saved if $wgCompressRevisions is set.
 595                                 $text = gzinflate( $text );
 596                         }
 597
 598                         if( in_array( 'object', $flags ) ) {
 599                                 # Generic compressed storage
 600                                 $obj = unserialize( $text );
 601                                 if ( !is_object( $obj ) ) {
 602                                         // Invalid object
 603                                         wfProfileOut( $fname );
 604                                         return false;
 605                                 }
 606                                 $text = $obj->getText();
 607                         }
 608
 609                         global $wgLegacyEncoding;
 610                         if( $wgLegacyEncoding && !in_array( 'utf-8', $flags ) ) {
 611                                 # Old revisions kept around in a legacy encoding?
 612                                 # Upconvert on demand.
 613                                 global $wgInputEncoding, $wgContLang;
 614                                 $text = $wgContLang->iconv( $wgLegacyEncoding, $wgInputEncoding, $text );
 615                         }
 616                 }
 617                 wfProfileOut( $fname );
 618                 return $text;
 619         }
 620
 621         /**
 622          * If $wgCompressRevisions is enabled, we will compress data.
 623          * The input string is modified in place.
 624          * Return value is the flags field: contains 'gzip' if the
 625          * data is compressed, and 'utf-8' if we're saving in UTF-8
 626          * mode.
 627          *
 628          * @static
 629          * @param mixed $text reference to a text
 630          * @return string
 631          */
 632         function compressRevisionText( &$text ) {
 633                 global $wgCompressRevisions;
 634                 $flags = array();
 635
 636                 # Revisions not marked this way will be converted
 637                 # on load if $wgLegacyCharset is set in the future.
 638                 $flags[] = 'utf-8';
 639
 640                 if( $wgCompressRevisions ) {
 641                         if( function_exists( 'gzdeflate' ) ) {
 642                                 $text = gzdeflate( $text );
 643                                 $flags[] = 'gzip';
 644                         } else {
 645                                 wfDebug( "Revision::compressRevisionText() -- no zlib support, not compressing\n" );
 646                         }
 647                 }
 648                 return implode( ',', $flags );
 649         }
 650
 651         /**
 652          * Insert a new revision into the database, returning the new revision ID
 653          * number on success and dies horribly on failure.
 654          *
 655          * @param Database $dbw
 656          * @return int
 657          */
 658         function insertOn( &$dbw ) {
 659                 global $wgDefaultExternalStore;
 660
 661                 $fname = 'Revision::insertOn';
 662                 wfProfileIn( $fname );
 663
 664                 $data = $this->mText;
 665                 $flags = Revision::compressRevisionText( $data );
 666
 667                 # Write to external storage if required
 668                 if ( $wgDefaultExternalStore ) {
 669                         if ( is_array( $wgDefaultExternalStore ) ) {
 670                                 // Distribute storage across multiple clusters
 671                                 $store = $wgDefaultExternalStore[mt_rand(0, count( $wgDefaultExternalStore ) - 1)];
 672                         } else {
 673                                 $store = $wgDefaultExternalStore;
 674                         }
 675                         // Store and get the URL
 676                         $data = ExternalStore::insert( $store, $data );
 677                         if ( !$data ) {
 678                                 # This should only happen in the case of a configuration error, where the external store is not valid
 679                                 throw new MWException( "Unable to store text to external storage $store" );
 680                         }
 681                         if ( $flags ) {
 682                                 $flags .= ',';
 683                         }
 684                         $flags .= 'external';
 685                 }
 686
 687                 # Record the text (or external storage URL) to the text table
 688                 if( !isset( $this->mTextId ) ) {
 689                         $old_id = $dbw->nextSequenceValue( 'text_old_id_val' );
 690                         $dbw->insert( 'text',
 691                                 array(
 692                                         'old_id'    => $old_id,
 693                                         'old_text'  => $data,
 694                                         'old_flags' => $flags,
 695                                 ), $fname
 696                         );
 697                         $this->mTextId = $dbw->insertId();
 698                 }
 699
 700                 # Record the edit in revisions
 701                 $rev_id = isset( $this->mId )
 702                         ? $this->mId
 703                         : $dbw->nextSequenceValue( 'rev_rev_id_val' );
 704                 $dbw->insert( 'revision',
 705                         array(
 706                                 'rev_id'         => $rev_id,
 707                                 'rev_page'       => $this->mPage,
 708                                 'rev_text_id'    => $this->mTextId,
 709                                 'rev_comment'    => $this->mComment,
 710                                 'rev_minor_edit' => $this->mMinorEdit ? 1 : 0,
 711                                 'rev_user'       => $this->mUser,
 712                                 'rev_user_text'  => $this->mUserText,
 713                                 'rev_timestamp'  => $dbw->timestamp( $this->mTimestamp ),
 714                                 'rev_deleted'    => $this->mDeleted,
 715                                 'rev_len'            => $this->mSize,
 716                         ), $fname
 717                 );
 718
 719                 $this->mId = !is_null($rev_id) ? $rev_id : $dbw->insertId();
 720                 wfProfileOut( $fname );
 721                 return $this->mId;
 722         }
 723
 724         /**
 725          * Lazy-load the revision's text.
 726          * Currently hardcoded to the 'text' table storage engine.
 727          *
 728          * @return string
 729          * @access private
 730          */
 731         function loadText() {
 732                 $fname = 'Revision::loadText';
 733                 wfProfileIn( $fname );
 734
 735                 // Caching may be beneficial for massive use of external storage
 736                 global $wgRevisionCacheExpiry, $wgMemc;
 737                 $key = wfMemcKey( 'revisiontext', 'textid', $this->getTextId() );
 738                 if( $wgRevisionCacheExpiry ) {
 739                         $text = $wgMemc->get( $key );
 740                         if( is_string( $text ) ) {
 741                                 wfProfileOut( $fname );
 742                                 return $text;
 743                         }
 744                 }
 745
 746                 // If we kept data for lazy extraction, use it now...
 747                 if ( isset( $this->mTextRow ) ) {
 748                         $row = $this->mTextRow;
 749                         $this->mTextRow = null;
 750                 } else {
 751                         $row = null;
 752                 }
 753
 754                 if( !$row ) {
 755                         // Text data is immutable; check slaves first.
 756                         $dbr = wfGetDB( DB_SLAVE );
 757                         $row = $dbr->selectRow( 'text',
 758                                 array( 'old_text', 'old_flags' ),
 759                                 array( 'old_id' => $this->getTextId() ),
 760                                 $fname);
 761                 }
 762
 763                 if( !$row ) {
 764                         // Possible slave lag!
 765                         $dbw = wfGetDB( DB_MASTER );
 766                         $row = $dbw->selectRow( 'text',
 767                                 array( 'old_text', 'old_flags' ),
 768                                 array( 'old_id' => $this->getTextId() ),
 769                                 $fname);
 770                 }
 771
 772                 $text = Revision::getRevisionText( $row );
 773
 774                 if( $wgRevisionCacheExpiry ) {
 775                         $wgMemc->set( $key, $text, $wgRevisionCacheExpiry );
 776                 }
 777
 778                 wfProfileOut( $fname );
 779
 780                 return $text;
 781         }
 782
 783         /**
 784          * Create a new null-revision for insertion into a page's
 785          * history. This will not re-save the text, but simply refer
 786          * to the text from the previous version.
 787          *
 788          * Such revisions can for instance identify page rename
 789          * operations and other such meta-modifications.
 790          *
 791          * @param Database $dbw
 792          * @param int      $pageId ID number of the page to read from
 793          * @param string   $summary
 794          * @param bool     $minor
 795          * @return Revision
 796          */
 797         function newNullRevision( &$dbw, $pageId, $summary, $minor ) {
 798                 $fname = 'Revision::newNullRevision';
 799                 wfProfileIn( $fname );
 800
 801                 $current = $dbw->selectRow(
 802                         array( 'page', 'revision' ),
 803                         array( 'page_latest', 'rev_text_id' ),
 804                         array(
 805                                 'page_id' => $pageId,
 806                                 'page_latest=rev_id',
 807                                 ),
 808                         $fname );
 809
 810                 if( $current ) {
 811                         $revision = new Revision( array(
 812                                 'page'       => $pageId,
 813                                 'comment'    => $summary,
 814                                 'minor_edit' => $minor,
 815                                 'text_id'    => $current->rev_text_id,
 816                                 ) );
 817                 } else {
 818                         $revision = null;
 819                 }
 820
 821                 wfProfileOut( $fname );
 822                 return $revision;
 823         }
 824
 825         /**
 826          * Determine if the current user is allowed to view a particular
 827          * field of this revision, if it's marked as deleted.
 828          * @param int $field one of self::DELETED_TEXT,
 829          *                          self::DELETED_COMMENT,
 830          *                          self::DELETED_USER
 831          * @return bool
 832          */
 833         function userCan( $field ) {
 834                 if( ( $this->mDeleted & $field ) == $field ) {
 835                         global $wgUser;
 836                         $permission = ( $this->mDeleted & self::DELETED_RESTRICTED ) == self::DELETED_RESTRICTED
 837                                 ? 'hiderevision'
 838                                 : 'deleterevision';
 839                         wfDebug( "Checking for $permission due to $field match on $this->mDeleted\n" );
 840                         return $wgUser->isAllowed( $permission );
 841                 } else {
 842                         return true;
 843                 }
 844         }
 845
 846
 847         /**
 848          * Get rev_timestamp from rev_id, without loading the rest of the row
 849          * @param integer $id
 850          */
 851         static function getTimestampFromID( $id ) {
 852                 $dbr = wfGetDB( DB_SLAVE );
 853                 $timestamp = $dbr->selectField( 'revision', 'rev_timestamp',
 854                         array( 'rev_id' => $id ), __METHOD__ );
 855                 if ( $timestamp === false ) {
 856                         # Not in slave, try master
 857                         $dbw = wfGetDB( DB_MASTER );
 858                         $timestamp = $dbw->selectField( 'revision', 'rev_timestamp',
 859                                 array( 'rev_id' => $id ), __METHOD__ );
 860                 }
 861                 return $timestamp;
 862         }
 863
 864         static function countByPageId( $db, $id ) {
 865                 $row = $db->selectRow( 'revision', 'COUNT(*) AS revCount',
 866                         array( 'rev_page' => $id ), __METHOD__ );
 867                 if( $row ) {
 868                         return $row->revCount;
 869                 }
 870                 return 0;
 871         }
 872
 873         static function countByTitle( $db, $title ) {
 874                 $id = $title->getArticleId();
 875                 if( $id ) {
 876                         return Revision::countByPageId( $db, $id );
 877                 }
 878                 return 0;
 879         }
 880 }
 881
 882 /**
 883  * Aliases for backwards compatibility with 1.6
 884  */
 885 define( 'MW_REV_DELETED_TEXT', Revision::DELETED_TEXT );
 886 define( 'MW_REV_DELETED_COMMENT', Revision::DELETED_COMMENT );
 887 define( 'MW_REV_DELETED_USER', Revision::DELETED_USER );
 888 define( 'MW_REV_DELETED_RESTRICTED', Revision::DELETED_RESTRICTED );
 889
 890
 891